MULTIPLE-CHIP EXCITATION SYSTEMS FOR WHITE LIGHT EMITTING DIODES (LEDs)

• US 20090224652A1
• Filed: 03/04/2009
• Published: 09/10/2009
• Est. Priority Date: 03/07/2008
• Status: Active Grant

• Current Assignee: Intematix Corporation
• Original Assignee: Intematix Corporation
• Inventors: Chen, Li-De, Li, Yi-Qun, Wang, Gang
• Granted Patent: US 8,567,973 B2
• Time in Patent Office: Days
• US Class Current: 313/498
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/7733 with alkali or alkaline earth metals
• CPC Class Codes: C09K 11/77342 Silicates
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: C09K 11/7739 with halogens
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: C09K 11/77924 Aluminosilicates
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

Embodiments of the present invention are directed toward white light illumination systems (so called “white LEDs”) that comprise a multi-chip excitation source and a phosphor package. In a two-chip source, the two LEDs may be UV-emitting and blue emitting, or blue-emitting and green-emitting. The phosphor package is configured to emit photoluminescence in wavelengths ranging from about 440 nm to about 700 nm upon co-excitation from the first and second radiation sources. The photoluminescence emitted by the phosphors is at least 40 percent of the total power in the white light illumination, and the portion of the total power in the white light illumination contributed by the first and second radiation sources (LEDs) is less than about 60 percent. This ratio can vary in alternative embodiments, and includes 50/50, 60/40, 70/30, and 80/20, respectively. The white light illumination emitted by the system has in one embodiment a color rendering index (CRI) greater than about 90.

Claims

1. A white light illumination system comprising a multi-chip excitation source and a phosphor package, the multi-chip excitation source comprising:

a first radiation source for providing co-excitation radiation to the phosphor package, the source emitting in wavelengths ranging from about 250 nm to about 410 nm;

a second radiation source for providing co-excitation radiation to the phosphor package, the source emitting in wavelengths ranging from about 410 nm to about 540 nm; and

a phosphor package configured to emit photoluminescence in wavelengths ranging from about 440 nm to about 700 nm upon co-excitation from the first and second radiation sources.

2. The white light illumination system of claim 1, wherein the phosphor package includes at least one phosphor selected from the group consisting of a blue emitting phosphor, a green emitting phosphor, a yellow-green emitting phosphor, an orange emitting phosphor, and a red emitting phosphor, including combinations thereof.

3. The white light illumination system of claim 1, wherein the white light illumination emitted by the system has a color rendering index (CRI) greater than about 90.

4. The white light illumination system of claim 1, wherein the white light illumination emitted by the system has a color rendering index (CRI) greater than about 80.

5. The white light illumination system of claim 1, wherein the white light illumination emitted by the system has a color rendering index (CRI) greater than about 70.

6. The white light illumination system of claim 1, wherein the photoluminescence emitted by the phosphor package is at least 40 percent of the total power in the white light illumination, and the portion of the total power in the white light illumination contributed by the first and second radiation sources is less than about 60 percent.

7. The white light illumination system of claim 1, wherein the photoluminescence emitted by the phosphor package is at least 50 percent of the total power in the white light illumination, and the portion of the total power in the white light illumination contributed by the first and second radiation sources is less than about 50 percent.

8. The white light illumination system of claim 1, wherein the photoluminescence emitted by the phosphor package is at least 60 percent of the total power in the white light illumination, and the portion of the total power in the white light illumination contributed by the first and second radiation sources is less than about 40 percent.

9. The white light illumination system of claim 1, wherein the photoluminescence emitted by the phosphor package is at least 70 percent of the total power in the white light illumination, and the portion of the total power in the white light illumination contributed by the first and second radiation sources is less than about 30 percent.

10. The white light illumination system of claim 1, wherein the photoluminescence emitted by the phosphor package is at least 80 percent of the total power in the white light illumination, and the portion of the total power in the white light illumination contributed by the first and second radiation sources is less than about 20 percent.

11. A white light illumination system comprising a multi-chip excitation source and a phosphor package, the multi-chip excitation source comprising:

a first radiation source for providing co-excitation radiation to the phosphor package, the source emitting in wavelengths ranging from about 410 nm to about 480 nm;

a second radiation source for providing co-excitation radiation to the phosphor package, the source emitting in wavelengths ranging from about 480 nm to about 540 nm; and

a phosphor package configured to emit photoluminescence in wavelengths ranging from about 440 nm to about 700 nm upon co-excitation from the first and second radiation sources.

12. The white light illumination system of claim 11, wherein the phosphor package includes at least one phosphor selected from the group consisting of a blue emitting phosphor, a green emitting phosphor, a yellow-green emitting phosphor, an orange emitting phosphor, and a red emitting phosphor, including combinations thereof.

13. The white light illumination system of claim 11, wherein the white light illumination emitted by the system has a color rendering index (CRI) greater than about 90.

14. The white light illumination system of claim 11, wherein the white light illumination emitted by the system has a color rendering index (CRI) greater than about 80.

15. The white light illumination system of claim 11, wherein the white light illumination emitted by the system has a color rendering index (CRI) greater than about 70.

16. The white light illumination system of claim 11, wherein the photoluminescence emitted by the phosphor package is at least 40 percent of the total power in the white light illumination, and the portion of the total power in the white light illumination contributed by the first and second radiation sources is less than about 60 percent.

17. The white light illumination system of claim 11, wherein the photoluminescence emitted by the phosphor package is at least 50 percent of the total power in the white light illumination, and the portion of the total power in the white light illumination contributed by the first and second radiation sources is less than about 50 percent.

18. The white light illumination system of claim 11, wherein the photoluminescence emitted by the phosphor package is at least 60 percent of the total power in the white light illumination, and the portion of the total power in the white light illumination contributed by the first and second radiation sources is less than about 40 percent.

19. The white light illumination system of claim 11, wherein the photoluminescence emitted by the phosphor package is at least 70 percent of the total power in the white light illumination, and the portion of the total power in the white light illumination contributed by the first and second radiation sources is less than about 30 percent.

20. The white light illumination system of claim 11, wherein the photoluminescence emitted by the phosphor package is at least 80 percent of the total power in the white light illumination, and the portion of the total power in the white light illumination contributed by the first and second radiation sources is less than about 20 percent.